Channel Bonding in Multiple-Wavelength Passive Optical Networks (PONs)

ABSTRACT

An apparatus comprises: a processor configured to: select a first channel from among a plurality of channels in a network, and generate a first message assigning a first grant corresponding to the first channel; a transmitter coupled to the processor and configured to transmit the first message; and a receiver coupled to the processor and configured to receive a second message on the first channel and in response to the first message. A method comprises: selecting a first channel from among a plurality of channels in a network; generating a first message assigning a first grant corresponding to the first channel; transmitting the first message; and receiving a second message on the first channel in response to the first message

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent applicationNo. 62/329,011 filed on Apr. 28, 2016 by Futurewei Technologies, Inc.and titled “Granting Mechanisms For Multi-Lane Passive Optical Networks(PONs),” which is incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

A PON is one system for providing network access over the last mile,which is the final portion of a telecommunications network that deliverscommunication to customers. A PON is a P2MP network comprising an OLT ata CO, ONUs at the user premises, and an ODN coupling the OLT to theONUs. PONs may also comprise RNs located between the OLTs and the ONUs,for instance at the end of roads where multiple customers reside.

NG-PONs may combine TDM and WDM to support higher capacities so thatincreased numbers of users can be served by a single OLT with sufficientbandwidth per user. In such a TWDM PON, a WDM PON may be overlaid on topof a TDM PON. In other words, different wavelengths may be multiplexedtogether to share a single feeder fiber, and each wavelength may beshared by multiple users using TDM.

SUMMARY

In one embodiment, the disclosure includes an apparatus comprising: aprocessor configured to: select a first channel from among a pluralityof channels in a network, and generate a first message assigning a firstgrant corresponding to the first channel; a transmitter coupled to theprocessor and configured to transmit the first message; and a receivercoupled to the processor and configured to receive a second message onthe first channel in response to the first message. In some embodiments,wherein the first message is a discovery gate message comprising achannel assignment field, a grant start time field, and a channelinformation field, wherein the channel assignment field indicates thefirst channel for upstream transmission, wherein the grant start timefield indicates when to transmit on the first channel, and wherein thechannel information field indicates channel-related information; thechannel-related information is at least one of a channel rate, a channelassociation, or a channel priority; the first message is a gate messagecomprising a channel assignment field and a grant start time field,wherein the channel assignment field indicates the first channel forupstream transmission, and wherein the grant start time field indicateswhen to transmit on the first channel; the second message is a reportmessage comprising a channel assignment field and a queue report field,wherein the channel assignment field indicates the first channel, andwherein the queue report field indicates a queue report for the firstchannel; the processor is further configured to select a second channelfrom among the channels, and wherein the first message further assigns asecond grant corresponding to the second channel; the transmitter isfurther configured to transmit the first message on the first channel;the transmitter is further configured to transmit the first message on asecond channel from among the channels; the apparatus is an OLT, andwherein the network is a PON; the transmitter is further configured tofurther transmit the first message to an ONU comprising a plurality ofONU transmitters, wherein the ONU transmitters comprise a firsttransmitter corresponding to the first channel, and wherein the firstmessage instructs the ONU to disable all of the ONU transmitters exceptfor the first transmitter.

In another embodiment, the disclosure includes a method comprising:selecting a first channel from among a plurality of channels in anetwork; generating a first message assigning a first grantcorresponding to the first channel; transmitting the first message; andreceiving a second message on the first channel and in response to thefirst message. In some embodiments, the first message is a discoverygate message comprising a channel assignment field, a grant start timefield, and a channel information field, wherein the channel assignmentfield indicates the first channel for upstream transmission, wherein thegrant start time field indicates when to transmit on the first channel,and wherein the channel information field indicates channel-relatedinformation; the first message is a gate message comprising a channelassignment field and a grant start time field, wherein the channelassignment field indicates the first channel for upstream transmission,and wherein the grant start time field indicates when to transmit on thefirst channel; the second message is a report message comprising achannel assignment field and a queue report field, wherein the channelassignment field indicates the first channel, and wherein the queuereport field indicates a queue report for the first channel; the methodfurther comprises selecting a second channel from among the channels,wherein the first message further assigns a second grant correspondingto the second channel; an OLT implements the method, wherein the networkis a PON, wherein the transmitting comprises transmitting the firstmessage to an ONU comprising a plurality of ONU transmitters, whereinthe ONU transmitters comprise a first transmitter corresponding to thefirst channel, and wherein the first message instructs the ONU todisable all of the ONU transmitters except for the first transmitter.

In yet another embodiment, the disclosure includes an ONU comprising: areceiver configured to receive a first message assigning a first grantcorresponding to a first channel selected from among a plurality ofchannels; a processor coupled to the receiver and configured to: processthe first message, and generate a second message; and a transmittercoupled to the processor and configured to transmit the second messageon the first channel and according to the first grant. In someembodiments, the first message further assigns a second grantcorresponding to a second channel selected from among the channels,wherein the processor is further configured to generate a third message,and wherein the transmitter is further configured to transmit the thirdmessage on the second channel and according to the second grant; thefirst message is a gate message comprising a channel assignment fieldand a grant start time field, wherein the channel assignment fieldindicates the first channel for upstream transmission, and wherein thegrant start time field indicates when to transmit on the first channel;the second message is a report message comprising a channel assignmentfield and a queue report field, wherein the channel assignment fieldindicates the first channel, and wherein the queue report fieldindicates a queue report for the first channel.

Any of the above embodiments may be combined with any of the other aboveembodiments to create a new embodiment. These and other features will bemore clearly understood from the following detailed description taken inconjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a schematic diagram of a PON.

FIG. 2 is a graph demonstrating an upstream channel bonding scheme.

FIG. 3 is a message sequence diagram illustrating registration andreporting of an ONU.

FIG. 4 is an extended discovery gate message according to an embodimentof the disclosure.

FIG. 5 is the channel assignment field in FIG. 4.

FIG. 6 is an extended gate message according to an embodiment of thedisclosure.

FIG. 7 is an extended gate message according to another embodiment ofthe disclosure.

FIG. 8 is a channel assignment field according to an embodiment of thedisclosure.

FIG. 9 is an extended report message according to an embodiment of thedisclosure.

FIG. 10 is the channel assignment field in FIG. 9.

FIG. 11 is a flowchart illustrating a method of channel bonding in amultiple-wavelength PON according to an embodiment of the disclosure.

FIG. 12 is a schematic diagram of a device according to an embodiment ofthe disclosure.

FIG. 13 is a gate message according to an embodiment of the disclosure.

DETAILED DESCRIPTION

It should be understood at the outset that, although an illustrativeimplementation of one or more embodiments are provided below, thedisclosed systems and/or methods may be implemented using any number oftechniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

The following abbreviations and initialisms apply:

-   -   ASIC: application-specific integrated circuit    -   CO: central office    -   CPU: central processing unit    -   DSP: digital signal processor    -   EO: electrical-to-optical    -   EPON: Ethernet PON    -   FCS: frame check sequence    -   G, Gb/s: gigabit(s) per second    -   ID: identifier    -   IEEE: Institute of Electrical and Electronics Engineers    -   LLID: logical link ID    -   MPCP: Multi-Point Control Protocol    -   NG-PON: next-generation PON    -   ODN: optical distribution network    -   OE: optical-to-electrical    -   OLT: optical line terminal    -   ONT: optical network terminal    -   ONU: optical network unit    -   opcode: operation code    -   PON: passive optical network    -   P2MP: point-to-multipoint    -   RAM: random-access memory    -   RN: remote node    -   ROM: read-only memory    -   RX: receiver unit    -   SRAM: static RAM    -   sync: synchronization    -   TCAM: ternary content-addressable memory    -   TDM: time-division multiplexing    -   TWDM: time- and wavelength-division multiplexing    -   TX: transmitter unit    -   WDM: wavelength-division multiplexing.

FIG. 1 is a schematic diagram of a PON 100. The PON 100 comprises an OLT110, a plurality of ONUs 120, and an ODN 130 that couples the OLT 110 tothe ONUs 120. The PON 100 is a communications network that may notrequire active components to distribute data between the OLT 110 and theONUs 120. Instead, the PON 100 may use passive optical components in theODN 130 to distribute data between the OLT 110 and the ONUs 120.

The OLT 110 communicates with the ONUs 120 and another network.Specifically, the OLT 110 is an intermediary between the other networkand the ONUs 120. For instance, the OLT 110 forwards data received fromthe other network to the ONUs 120 and forwards data received from theONUs 120 to the other network. The OLT 110 comprises a transmitter and areceiver. When the other network uses a network protocol that isdifferent from the protocol used in the PON 100, the OLT 110 comprises aconverter that converts the network protocol to the PON protocol andvice versa. The OLT 110 is typically located at a central location suchas a CO, but it may also be located at other suitable locations.

The ODN 130 is a data distribution system that comprises optical fibercables, couplers, splitters, distributors, and other suitablecomponents. The components include passive optical components that donot require power to distribute signals between the OLT 110 and the ONUs120. Alternatively, the components include active components such asoptical amplifiers that do require power. The ODN 130 extends from theOLT 110 to the ONUs 120 in a branching configuration as shown, but theODN 130 may be configured in any other suitable P2MP configuration.

The ONUs 120 communicate with the OLT 110 and customers and act asintermediaries between the OLT 110 and the customers. For instance, theONUs 120 forward data from the OLT 110 to the customers and forward datafrom the customers to the OLT 110. The ONUs 120 comprise opticaltransmitters that convert electrical signals into optical signals andtransmit the optical signals to the OLT 110, and the ONUs 120 compriseoptical receivers that receive optical signals from the OLT 110 andconvert the optical signals into electrical signals. The ONUs 120further comprise second transmitters that transmit the electricalsignals to the customers and second receivers that receive electricalsignals from the customers. ONUs 120 and ONTs are similar, and the termsmay be used interchangeably. The ONUs 120 are typically located atdistributed locations such as customer premises, but they may also belocated at other suitable locations.

IEEE P802.3ca 100G-EPON Task Force is tasked with defining physicallayer specifications and management parameters for 25G, 50G, and 100Gmultiple-wavelength PONs. Such PONs support channel bonding, whichrefers to the OLT 110 assigning multiple channels to an ONU 120 to useat the same time and refers to an ONU 120 using multiple channels at thesame time. The ONU 120 may perform channel-bonded reception in adownstream direction from the OLT 110 to the ONU 120, or channel-bondedtransmission in an upstream direction from the ONU 120 to the OLT 110.For a 100G-EPON, each channel, or lane, corresponds to a differentwavelength and provides up to a 25G data rate. Thus, an ONU 120transmits and receives using one channel to achieve a 25G data rate, theONU 120 transmits and receives using two channels to achieve a 50G datarate, the ONU 120 transmits and receives using three channels to achievea 75G data rate, and the ONU 120 transmits and receives using fourchannels to achieve a 100G data rate.

FIG. 2 is a graph 200 demonstrating an upstream channel bonding scheme.The x-axis represents time in constant units, and the y-axis representschannels in constant units. The PON 100 employs the upstream channelbonding scheme. In this case, the PON 100 comprises seven ONUs 120denoted as ONU 1-ONU 7. The upstream channel bonding scheme useschannels 0-3 corresponding to wavelengths λ₀-λ₄. Each channel provides a25G data rate. At time t₁, ONU 1 transmits using channel 3, ONU 2transmits using both channel 0 and channel 2, and ONU 3 transmits usingchannel 1. At time t₂, ONU 2 transmits using both channel 0 and channel2, ONU 3 transmits using channel 1, and ONU 6 transmits using channel 3.At time t₃, ONU 2 transmits using both channel 0 and channel 2, ONU 6transmits using channel 3, and ONU 7 transmits using channel 1. At timet₄, ONU 5 transmits using channels 0-3. However, there remains a need toimplement channel bonding in the upstream direction.

Disclosed herein are embodiments for channel bonding inmultiple-wavelength PONs. The disclosed embodiments extend IEEE MPCPmessages to implement upstream channel bonding. A discovery gate messageis extended to include a channel assignment field, or lane flag field,for the OLT 110 to grant upstream channels to the ONUs 120 fordiscovery. A gate message is extended to include a channel assignmentfield for the OLT 110 to grant upstream channels to the ONUs 120 fornormal operation. In this context, normal operation refers to operationother than during discovery. For instance, normal operation comprisescommunication of user data that is to be communicated beyond the PON 100and to a larger network. A report message is extended to include achannel assignment field for the ONUs 120 to report queue statuses ofchannels to the OLT 110. Though specific numbers of channels arediscussed, the disclosed embodiments apply to any suitable number ofchannels. In addition, though channels are discussed as being associatedwith wavelengths, channels may be associated with other concepts.Furthermore, though upstream channel bonding is discussed, the sameprinciples apply to downstream channel bonding. Finally, though extendedIEEE MPCP messages are discussed, the same principles apply to othertypes of extended messages or new messages.

FIG. 3 is a message sequence diagram 300 illustrating registration andreporting of an ONU 120. At step 310, the OLT 110 transmits to the ONUs120 a discovery gate message granting transmission windows fordiscovery. At step 320, an ONU 120 transmits to the OLT 110 a registerrequest message requesting registration in the PON 100 and indicatingcapabilities of the ONU 120. At step 330, the OLT 110 transmits to theONU 120 a register message instructing the ONU 120 to register andassigning IDs to the ONU 120. At step 340, the OLT 110 transmits to theONU 120 a gate message to grant transmission windows for the ONU 120 totransmit a register acknowledgment message.

At step 350, the ONU 120 transmits to the OLT 110 a registeracknowledgment message acknowledging the register message and echoingthe IDs. By completing step 350, the ONU 120 completes registration andenters normal operation. At step 360, the OLT 110 transmits to the ONU120 a gate message instructing the ONU 120 to grant transmission windowsfor normal transmission. Finally, at step 370, the ONU 120 transmits tothe OLT 110 a report message indicating queue statuses. The messages aredescribed in IEEE 802.3-2012, Section 5, 2012 (“802.3-2012”), which isincorporated by reference. The discovery gate message at step 310; thegate message at steps 340, 360; and the report message at step 370 areextended as described further below.

FIG. 4 is an extended discovery gate message 400 according to anembodiment of the disclosure. The extended discovery gate message 400implements the discovery gate message in step 310 in FIG. 3. The OLT 110transmits the extended discovery gate message 400 to the ONU 120 togrant transmission windows in multiple channels for discovery. Theextended discovery gate message 400 comprises a destination addressfield 405, a source address field 410, a length/type field 415, anopcode field 420, a timestamp field 425, a channel assignment field 430,a number of grants/flags field 435, a grant #1 start time field 440, agrant #1 length field 445, a sync time field 450, a discoveryinformation field 455, a channel information field 460, a pad/reservedfield 465, and an FCS field 470.

The channel assignment field 430 may be a bitmap and indicates achannel, for instance channel 1 corresponding to wavelength λ₁, for theONU 120 to transmit on during discovery. The channel assignment field430 is described further below. The grant #1 start time field 440indicates when the ONU 120 can transmit a first signal on the channelindicated in the channel assignment field 430, and the grant #1 lengthfield 445 indicates how long the ONU 120 can transmit the first signalon the channel indicated in the channel assignment field 430. Thechannel information field 460 indicates channel-related information ofthe channel indicated in the channel assignment field 430. Thechannel-related information is a channel rate, a channel association, achannel priority, or other suitable information.

The OLT 110 may transmit the extended discovery gate message 400 to theONU 120 whether or not the ONU 120 is capable of channel bonding. If theOLT 110 determines that it should assign multiple channels to the ONU120 for discovery, then the channel assignment field 430 indicatesmultiple channels. Alternatively, if the OLT 110 determines that itshould assign multiple channels to the ONU 120 for discovery, then thechannel assignment field 430 indicates one channel and the OLT 110transmits the extended discovery gate message 400 to the ONU 120 foreach channel.

FIG. 5 is the channel assignment field 430 in FIG. 4. The channelassignment field 430 comprises bit 0 corresponding to channel 0, bit 1corresponding to channel 1, bit 2 corresponding to channel 2, bit 3corresponding to channel 3, and bits 4-7 that are reserved. For each ofbits 0-3, a binary 0 indicates that the corresponding channel is not fordiscovery and a binary 1 indicates that the corresponding channel is fordiscovery. Bits 4-7 may be padded with 0s or 1s. For example, when bits0-7 are equal to 00000100, channels 0-1 and 3 are not for discovery andchannel 2 is for discovery.

FIG. 6 is an extended gate message 600 according to an embodiment of thedisclosure. The extended gate message 600 implements the gate message insteps 340, 360 in FIG. 3. The OLT 110 transmits the extended gatemessage 600 to the ONU 120 to grant transmission windows in multiplechannels for normal operation. The extended gate message 600 comprises adestination address field 605, a source address field 610, a length/typefield 615, an opcode field 620, a timestamp field 625, a channelassignment field 630, a number of grants/flags field 635, a grant #1start time field 640, a grant #1 length field 645, a grant #2 start timefield 650, a grant #2 length field 655, a grant #3 start time field 660,a grant #3 length field 665, a grant #4 start time field 670, a grant #4length field 675, a pad/reserved field 680, and an FCS field 685.

The channel assignment field 630 may be a bitmap and indicates achannel, for instance channel 1 corresponding to wavelength λ₁, for theONU 120 to transmit on during normal operation. The channel assignmentfield 630 is described further below. The grant #1 start time field 640indicates when the ONU 120 can transmit a first signal on the channelindicated in the channel assignment field 630, and the grant #1 lengthfield 645 indicates how long the ONU 120 can transmit the first signalon the channel indicated in the channel assignment field 630. The grant#2 start time field 650 and the grant #2 length field 655 are similarfor a second signal, the grant #3 start time field 660 and the grant #3length field 665 are similar for a third signal, and the grant #4 starttime field 670 and the grant #4 length field 675 are similar for afourth signal.

The OLT 110 may transmit the extended gate message 600 to the ONU 120whether or not the ONU 120 is capable of channel bonding. If the OLT 110determines that it should assign multiple channels to the ONU 120 fornormal operation, then the channel assignment field 630 indicatesmultiple channels. Alternatively, if the OLT 110 determines that itshould assign multiple channels to the ONU 120 for normal operation,then the channel assignment field 630 indicates one channel and the OLT110 transmits the extended gate message 600 to the ONU 120 for eachchannel.

FIG. 7 is an extended gate message 700 according to another embodimentof the disclosure. The extended gate message 700 is similar to theextended gate message 600 in FIG. 6. Specifically, the extended gatemessage 700 comprises a destination address field 703, a source addressfield 705, a length/type field 707, an opcode field 710, a timestampfield 713, a number of grants/flags field 715, a grant #1 start timefield 720, a grant #1 length field 723, a grant #2 start time field 727,a grant #2 length field 730, a grant #3 start time field 735, a grant #3length field 737, a grant #4 start time field 743, a grant #4 lengthfield 745, a pad/reserved field 747, and an FCS field 750. However,unlike the extended gate message 600, the extended gate message 700comprises a channel assignment field for each grant. Specifically, theextended gate message 700 comprises a channel assignment #1 field 717, achannel assignment #2 field 725, a channel assignment #3 field 733, anda channel assignment #4 field 740.

FIG. 8 is a channel assignment field 800 according to an embodiment ofthe disclosure. The channel assignment field 800 implements the channelassignment field 630 in FIG. 6 and the channel assignment #1 field 717,the channel assignment #2 field 725, the channel assignment #3 field733, and the channel assignment #4 field 740 in FIG. 7. The channelassignment field 800 comprises bit 0 corresponding to channel 0, bit 1corresponding to channel 1, bit 2 corresponding to channel 2, bit 3corresponding to channel 3, and bits 4-7 that are reserved. For each ofbits 0-3, a binary 0 indicates that the succeeding grant is not for thecorresponding channel and a binary 1 indicates that the succeeding grantis for the corresponding channel. Bits 4-7 may be padded with 0s or 1s.For example, when bits 0-7 are equal to 00000010, the grant is not forchannels 0 and 2-3, but is for channel 1.

FIG. 9 is an extended report message 900 according to an embodiment ofthe disclosure. The extended report message 900 implements the reportmessage in step 370 in FIG. 3. The ONU 120 transmits the extended reportmessage 900 to the OLT 110 to report queue statuses. The extended reportmessage 900 comprises a destination address field 905, a source addressfield 910, a length/type field 915, an opcode field 920, a timestampfield 925, a number of queue sets field 930, a channel assignment field935, a report bitmap field 940, a queue #0 report field 945, a queue #1report field 950, a queue #2 report field 955, a queue #3 report field960, a queue #4 report field 965, a queue #5 report field 970, a queue#6 report field 975, a queue #7 report field 980, a pad/reserved field985, and an FCS field 990.

The channel assignment field 935 may be a bitmap and indicates achannel, for instance channel 1 corresponding to wavelength λ₁, forwhich the ONU 120 is reporting queue statuses. The channel assignmentfield 935 is described further below. The queue #0 report field 945, thequeue #1 report field 950, the queue #2 report field 955, the queue #3report field 960, the queue #4 report field 965, the queue #5 reportfield 970, the queue #6 report field 975, and the queue #7 report field980 indicate successive queue reports for the channel indicated in thechannel assignment field 935.

The ONU 120 may transmit the extended report message 900 to the OLT 110whether or not the ONU 120 is capable of channel bonding. If the ONU 120is using multiple channels, then the extended report message 900comprises a set of a channel assignment field and a queue report fieldfor each channel. Alternatively, if the ONU 120 is using multiplechannels, then the channel assignment field 935 indicates one channeland the ONU 120 transmits the extended report message 900 to the OLT 110for each channel.

FIG. 10 is the channel assignment field 935 in FIG. 9. The channelassignment field 935 comprises bit 0 corresponding to channel 0, bit 1corresponding to channel 1, bit 2 corresponding to channel 2, bit 3corresponding to channel 3, and bits 4-7 that are reserved. For each ofbits 0-3, a binary 0 indicates that the succeeding queue reports are notfor the corresponding channel and a binary 1 indicates that thesucceeding queue reports are for the corresponding channel. Bits 4-7 maybe padded with 0s or 1s. For example, when bits 0-7 are equal to00000010, the grant is not for channels 0 and 2-3, but is for channel 1.

Using the extended discovery gate message 400, the extended gate message600, the extended gate message 700, and the extended report message 900,the OLT 110 and the ONUs 120 may implement channel bonding. The OLT 110assigns grants to the ONUs 120 in at least three different manners. In afirst manner, the OLT 110 selects a channel, for instance channel 0, asa control channel and communicates control information such as theextended discovery gate message 400, the extended gate message 600, andthe extended gate message 700 on channel 0. Thus, if the OLT 110 desiresto assign grants to an ONU 120 for both channel 0 and channel 2, thenthe OLT 110 does so by transmitting the extended discovery gate message400, the extended gate message 600, or the extended gate message 700 onchannel 0.

In a second manner, the OLT 110 transmits the extended discovery gatemessage 400, the extended gate message 600, and the extended gatemessage 700 to the ONU 120 on all channels. Thus, the OLT 110 treats allchannels equally and duplicates the extended discovery gate message 400,the extended gate message 600, and the extended gate message 700. In athird manner, the OLT 110 transmits the extended discovery gate message400, the extended gate message 600, and the extended gate message 700 tothe ONU 120 on the channel that the OLT 110 assigns the grants to.

Using the extended discovery gate message 400, the extended gate message600, the extended gate message 700, and the extended report message 900,the OLT 110 and the ONUs 120 may implement power conservation in theONUs 120. When traffic is light, an ONU 120 enters a power-saving mode.The ONU 120 periodically transmits the extended report message 900 tothe OLT 110 on one channel, for instance channel 1, to indicate that theother channels, for instance channels 0 and 2-3, are in a power-savingmode. The ONU 120 sets a value of the channel assignment field 935 to0000010 and sets values of the queue #1 report field 950, the queue #2report field 955, the queue #3 report field 960, the queue #4 reportfield 965, the queue #5 report field 970, the queue #6 report field 975,and the queue #7 report field 980 to 0.

The OLT 110 may desire to disable transceivers or transmitters of theONU 120, keep alive the ONU 120, or wake up the ONU 120. If the OLT 110desires to disable transceivers or transmitters of the ONU 120, then theOLT 110 may do so using the extended discovery gate message 400, theextended gate message 600, or the extended gate message 700. Thediscovery gate message 400 may instruct the ONU 120 to disable alltransceivers or transmitters except a transceiver or transmittercorresponding to a channel indicated in the channel assignment field430. The extended gate message 600 may instruct the ONU 120 to disableall transceivers or transmitters except a transceiver or transmittercorresponding to a channel indicated in the channel assignment field630. The extended gate message 700 may instruct the ONU 120 to disableall transceivers or transmitters except transceivers or transmitterscorresponding to channels indicated in the channel assignment field #1field 717, the channel assignment #2 field 725, the channel assignment#3 field 733, and the channel assignment #4 field 740.

If the OLT 110 desires to keep alive the ONU 120, then the OLT 110periodically transmits to the ONU 120 the extended gate message 600, theextended gate message 700, or another suitable message with a firstformat. For instance, for the extended gate message 600, the OLT 110sets a value of the channel assignment field 630 to all 1s and a valueof the number of grants/flags field 635 to 0. For the extended gatemessage 700, the OLT 110 sets a value of the number of grants/flagsfield 715 to 0 and sets a value of the channel assignment #1 field 717,the channel assignment #2 field 725, the channel assignment #3 field733, and the channel assignment #4 field 740 to all 1s.

If the OLT 110 desires to wake up the ONU 120, then the OLT 110transmits to the ONU 120 the extended gate message 600, the extendedgate message 700, or another suitable message with a second format. Forinstance, for the extended gate message 600, the OLT 110 sets a value ofthe channel assignment field 630 to 0000010 and a value of the number ofgrants/flags field 635 to 1. For the extended gate message 700, the OLT110 sets a value of the number of grants/flags field 715 to 1 and sets avalue of the channel assignment #1 field 717, the channel assignment #2field 725, the channel assignment #3 field 733, and the channelassignment #4 field 740 to 0000010.

FIG. 11 is a flowchart illustrating a method 1100 of channel bonding ina multiple-wavelength PON according to an embodiment of the disclosure.The OLT 110 performs the method 1100. At step 1110, a first channel isselected from among a plurality of channels in a network. For instance,the OLT 110 selects channel 1 from among channels 0-3 in the PON 100. Atstep 1120, a first message assigning a first grant corresponding to afirst channel is generated. For instance, the OLT 110 generates theextended discovery gate message 400, the extended gate message 600, orthe extended gate message 700. At step 1130, the first message istransmitted. For instance, the OLT 110 transmits the extended discoverygate message 400, the extended gate message 600, or the extended gatemessage 700 to an ONU 120. Finally, at step 1140, a second message isreceived on the first channel and in response to the first message. Forinstance, the OLT 110 receives a second message from the ONU 120 onchannel 1. The second message may be the extended report message 900.

FIG. 12 is a schematic diagram of a device 1200 according to anembodiment of the disclosure. The device 1200 may implement thedisclosed embodiments. The device 1200 comprises ingress ports 1210 andan RX 1220 coupled to the ingress ports 1210 for receiving data; aprocessor, logic unit, or CPU 1230 coupled to the RX 1220 to process thedata; a TX 1240 coupled to the processor 1230 and egress ports 1250coupled to the TX 1240 for transmitting the data. A memory 1260 iscoupled to the processor 1230 for storing the data. The device 1200 mayalso comprise OE components and EO components coupled to the ingressports 1210, the RX 1220, the TX 1240, and the egress ports 1250 foringress or egress of optical or electrical signals.

The processor 1230 is any suitable combination of hardware, middleware,firmware, or software. The processor 1230 comprises any combination ofone or more CPU chips, cores, FPGAs, ASICs, or DSPs. The processor 1230communicates with the ingress ports 1210, RX 1220, TX 1240, egress ports1250, and memory 1260. The processor 1230 comprises a channel bondingcomponent 1270, which implements the disclosed embodiments. Theinclusion of the channel bonding component 1270 therefore provides asubstantial improvement to the functionality of the device 1200 andeffects a transformation of the device 1200 to a different state.Alternatively, the memory 1260 stores the channel bonding component 1270as instructions, and the processor 1230 executes those instructions.

The memory 1260 comprises one or more disks, tape drives, or solid-statedrives. The device 1200 may use the memory 1260 as an over-flow datastorage device to store programs when the device 1200 selects thoseprograms for execution and to store instructions and data that thedevice 1200 reads during execution of those programs. The memory 1260may be volatile or non-volatile and may be any combination of ROM, RAM,TCAM, or SRAM.

In an example embodiment, an apparatus comprises: a processor elementconfigured to: select a first channel from among a plurality of channelsin a network, and generate a first message assigning a first grantcorresponding to the first channel; a transmitter element coupled to theprocessor element and configured to transmit the first message; and areceiver element coupled to the processor element and configured toreceive a second message on the first channel and in response to thefirst message.

A first component is directly coupled to a second component when thereare no intervening components, except for a line, a trace, or anothermedium between the first component and the second component. The firstcomponent is indirectly coupled to the second component when there areintervening components other than a line, a trace, or another mediumbetween the first component and the second component. The term “coupled”and its variants include both directly coupled and indirectly coupled.The use of the term “about” means a range including ±10% of thesubsequent number unless otherwise stated.

While several embodiments have been provided in the present disclosure,it may be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, components, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and may be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. An apparatus comprising: a processor configuredto: select a first channel from among a plurality of channels in anetwork, and generate a first message assigning a first grantcorresponding to the first channel; a transmitter coupled to theprocessor and configured to transmit the first message; and a receivercoupled to the processor and configured to receive a second message onthe first channel in response to the first message.
 2. The apparatus ofclaim 1, wherein the first message is a discovery gate messagecomprising a channel assignment field, a grant start time field, and achannel information field, wherein the channel assignment fieldindicates the first channel for upstream transmission, wherein the grantstart time field indicates when to transmit on the first channel, andwherein the channel information field indicates channel-relatedinformation.
 3. The apparatus of claim 2, wherein the channel-relatedinformation is at least one of a channel rate, a channel association, ora channel priority.
 4. The apparatus of claim 1, wherein the firstmessage is a gate message comprising a channel assignment field and agrant start time field, wherein the channel assignment field indicatesthe first channel for upstream transmission, and wherein the grant starttime field indicates when to transmit on the first channel.
 5. Theapparatus of claim 1, wherein the second message is a report messagecomprising a channel assignment field and a queue report field, whereinthe channel assignment field indicates the first channel, and whereinthe queue report field indicates a queue report for the first channel.6. The apparatus of claim 1, wherein the processor is further configuredto select a second channel from among the channels, and wherein thefirst message further assigns a second grant corresponding to the secondchannel.
 7. The apparatus of claim 1, wherein the transmitter is furtherconfigured to transmit the first message on the first channel.
 8. Theapparatus of claim 1, wherein the transmitter is further configured totransmit the first message on a second channel from among the channels.9. The apparatus of claim 1, wherein the apparatus is an optical lineterminal (OLT), and wherein the network is a passive optical network(PON).
 10. The apparatus of claim 9, wherein the transmitter is furtherconfigured to further transmit the first message to an optical networkunit (ONU) comprising a plurality of ONU transmitters, wherein the ONUtransmitters comprise a first transmitter corresponding to the firstchannel, and wherein the first message instructs the ONU to disable allof the ONU transmitters except for the first transmitter.
 11. A methodcomprising: selecting a first channel from among a plurality of channelsin a network; generating a first message assigning a first grantcorresponding to the first channel; transmitting the first message; andreceiving a second message on the first channel and in response to thefirst message.
 12. The method of claim 11, wherein the first message isa discovery gate message comprising a channel assignment field, a grantstart time field, and a channel information field, wherein the channelassignment field indicates the first channel for upstream transmission,wherein the grant start time field indicates when to transmit on thefirst channel, and wherein the channel information field indicateschannel-related information.
 13. The method of claim 11, wherein thefirst message is a gate message comprising a channel assignment fieldand a grant start time field, wherein the channel assignment fieldindicates the first channel for upstream transmission, and wherein thegrant start time field indicates when to transmit on the first channel.14. The method of claim 11, wherein the second message is a reportmessage comprising a channel assignment field and a queue report field,wherein the channel assignment field indicates the first channel, andwherein the queue report field indicates a queue report for the firstchannel.
 15. The method of claim 11, further comprising selecting asecond channel from among the channels, wherein the first messagefurther assigns a second grant corresponding to the second channel. 16.The method of claim 11, wherein an optical line terminal (OLT)implements the method, wherein the network is a passive optical network(PON), wherein the transmitting comprises transmitting the first messageto an optical network unit (ONU) comprising a plurality of ONUtransmitters, wherein the ONU transmitters comprise a first transmittercorresponding to the first channel, and wherein the first messageinstructs the ONU to disable all of the ONU transmitters except for thefirst transmitter.
 17. An optical network unit (ONU) comprising: areceiver configured to receive a first message assigning a first grantcorresponding to a first channel selected from among a plurality ofchannels; a processor coupled to the receiver and configured to: processthe first message, and generate a second message; and a transmittercoupled to the processor and configured to transmit the second messageon the first channel and according to the first grant.
 18. The ONU ofclaim 17, wherein the first message further assigns a second grantcorresponding to a second channel selected from among the channels,wherein the processor is further configured to generate a third message,and wherein the transmitter is further configured to transmit the thirdmessage on the second channel and according to the second grant.
 19. TheONU of claim 17, wherein the first message is a gate message comprisinga channel assignment field and a grant start time field, wherein thechannel assignment field indicates the first channel for upstreamtransmission, and wherein the grant start time field indicates when totransmit on the first channel.
 20. The ONU of claim 17, wherein thesecond message is a report message comprising a channel assignment fieldand a queue report field, wherein the channel assignment field indicatesthe first channel, and wherein the queue report field indicates a queuereport for the first channel.